This invention relates generally to the field of building blocks, usually formed of cementitious material, which are used as stacked components in the construction of walls and structures. More particularly, the invention relates to such articles which are shaped such that the blocks interlock or align when stacked.
Cementitious building blocks, often known as cement or concrete blocks, are well known in the masonry and construction fields. In the most common configuration, the blocks are rectangular with dimensions of approximately 8 inches in height and depth and 16 inches in length. The blocks are not solid but are provided with two vertically oriented openings separated by a lateral internal wall or web member, such that the blocks possess a shape similar to the number xe2x80x9c8xe2x80x9d with rectangular corners when viewed from the top or bottom. The open interiors reduce the weight of the block, allow less material to be consumed in their formation, and provide vertical channels in the finished wall structure for the passage of wiring, plumbing or conduits, or for receipt of filler materials such as poured concrete to increase strength, insulation or other properties. Such blocks have been in use for many years, and when properly joined by mortar interspersed between adjacent blocks they form extremely solid structures. Constructing a wall from discrete blocks requires a certain degree of skill, since wet mortar must be applied to the proper surfaces of the previously laid blocks and/or to the proper surfaces of the block to be laid, then the block must be positioned and aligned with the previously laid blocks such that the height of each row remains constant and such that the wall possesses a planar inner and outer surface.
Because the proper laying of block is a time-consuming, labor-intensive and skilled task, alternative block structures, configurations and systems have been developed which address one or more of these problems. One approach has been to provide mortarless blocks, i.e., blocks which interlock in a secure manner without the need for the addition of mortar or other bonding material between individual blocks. The blocks are usually constructed such that each possesses both male and female mating components, such as a pair of longitudinal channels on the top and a pair of longitudinal ridges on the bottom, so that the channels of the lower block receive the ridges of the block set above it. Other projection/recess or tongue/groove mating configurations are also known and utilized. Many systems use the interlocking blocks merely as forms to receive poured concrete, with the blocks often formed of polystyrene foam. Examples of such systems are seen in U.S. Pat. No. 5,901,520 to Abdul-Baki, U.S. Pat. No. 5,894,702 to Stenekes, U.S. Pat. No. 5,623,797 to Gravier et al., U.S. Pat. No. 5,457,926 to Jensen, U.S. Pat. No. 4,186,540 to Mullins, and U.S. Pat. No. 3,534,518 to Zagray. Mortarless systems have met with rather limited success, however, since conventional block-making equipment cannot produce blocks with less than a {fraction (1/16)} inch variation in height between individual blocks. Even such a small variation is enough to cause unacceptable deviation from plumb after only 3 or 4 courses. The use of mortar between blocks compensates for this variation, since the height of the mortar can be varied to properly position each block at the proper height. Mortar also serves to seal joints and provides a measure of flexural strength, so eliminating mortar is not necessarily beneficial.
Other systems of interlocking or aligning blocks have been developed where mortar or grout is still used in some degree to join adjacent blocks in a more secure manner beyond that provided by the interlocking or aligning structures alone. For example, Brooke in U.S. Pat. No. 800,067 discloses blocks having longitudinal tongue and groove alignment means along the edges, where mention is made that cement or grout is utilized to construct the wall. Buyer in U.S. Pat. No. 2,019,653 shows blocks having centralized raised bosses and corresponding sockets for alignment, where the bosses sockets have a flat surface bounded by two sloping lateral surfaces, where the flat and sloping surfaces abut directly when the blocks are stacked. A recess is provided along the horizontal joint between courses for receiving mortar or grout after the blocks have been stacked. Finally, Huag et al. in U.S. Pat. No. 4,787,189 shows another type of interlocking blocks where the center of the blocks have longitudinal tongue and groove configurations. A problem with the Brooke and Huag et al. systems is that both still require skilled application of the mortar in the right amount to the proper locations, since there is no provision in the designs to allow for excess or misplaced mortar. Any mortar which inadvertently falls into the tongue and groove areas will interfere with and prevent proper alignment of the blocks, necessitating the lifting of the block and removal of the excess material. The Buyer system is in effect a mortarless system, with all the inherent problems of those types, since the mortar or grout is not applied until after the blocks have been stacked. Should the mortar be applied prior to stacking, the Buyer design likewise provides no margin for application error, since the sloped surfaces make direct contact when the blocks are stacked and excessive or misplaced mortar will interfere with the proper fit and alignment.
Another similar type of self-aligning building block system is disclosed in my U.S. Pat. No. 6,223,493 issued May 1, 2001. The invention therein is a self-aligning cementitious block and a wall system of such blocks stacked and joined by mortar to form a vertically oriented wall structure, where the block comprises alignment means which correctly align the block relative to the blocks upon which it is stacked such that the side walls are parallel to the side walls of the lower blocks. The alignment means comprise projection members and recess members of corresponding configuration, where the projection members preferably extend downward from the two end walls and the middle wall a distance below the lower longitudinal edges of the side walls, and where the recess members are positioned on the tops of the end walls and middle wall, the recess members of inferior or lower blocks receiving the projection members of a superior or upper block stacked thereupon. Starter blocks with a flat underside and corner blocks are also provided. Such a design for the blocks has been found to be difficult to manufacture, and the extended projection member is subject to breaking if mishandled. Furthermore, the design is more difficult to stack on a pallet in a compact manner.
It is an object of this invention to provide a cementitious building block and system where the blocks are self-aligning and interlock to provide a wall structure having generally planar inner and outer wall surfaces, where the courses are easily maintained at plumb as the height of the wall increases. It is a further object to provide such a block and system where the blocks can be properly stacked in a fast and non-complicated manner, such that the task can be performed by relatively unskilled labor having only the most basic of mortar application skills. It is a further object to provide such a system where mortar is utilized to join adjacent blocks, such that the joints are sealed, flexural strength is enhanced, and variations in block height can be compensated for. These and other objects not expressly stated will be apparent based on the disclosure and description of the invention, its best mode and preferred embodiment, as set forth below.
The invention is a self-aligning cementitious block and a system of such blocks stacked and joined by mortar to form a vertically oriented wall structure, where the block comprises alignment means which correctly align the block relative to the blocks upon which it is stacked such that the side walls are parallel to the side walls of the lower blocks. The alignment means comprise tongue members and groove members of corresponding configuration, where the tongue members extend downward from the two end walls and the middle wall a distance below the lower longitudinal edges of the side walls, and where the groove members are positioned on the tops of the end walls and middle wall, the groove members of inferior or lower blocks receiving the tongue members of a superior or upper block stacked thereupon.
The tongue members comprise a planar, horizontally disposed, lower edge bounded by a pair of short, outwardly inclined first sloping side walls, and a pair of short, outwardly inclined second sloping side walls connecting the first sloping side walls to the lower edges or bottom of the block. The groove members comprise a planar lower edge or bottom bounded by a pair of short, outwardly inclined first sloping side walls, and a pair of short, outwardly inclined second sloping walls connecting the first sloping side walls to the upper edges or top of the block. The second sloping side walls on both the tongue member and groove member are more sloped or inclined, i.e., more horizontally or less vertically disposed, than the first sloping side walls. The depth of the groove members is less than the vertical height or length of the tongue members, and the lateral width of the tongue members is slightly less than the width of the groove members, such that when a block is placed atop another block or set of blocks the tongue member sloping walls and groove member sloping walls loosely mate. The alignment means insure that the blocks are properly oriented and the mortar bonds the blocks together.
Corner blocks are provided in the system, the corner blocks being identical to the standard block in regard to the tongue members on the end walls and the middle wall, and to the groove members on one end wall and the middle wall. The opposing end wall is an exterior end wall and has a planar upper lateral edge rather than a groove member. A pair of groove members of identical configuration are positioned in the side walls of the block between the middle wall and the end wall with the planar upper lateral edge. To form a corner, each superior corner block is positioned perpendicular to the inferior corner block, such that the tongue members extending beneath the middle and exterior end walls of the superior block align with the groove members positioned in the side walls of the inferior block. In this manner the exterior end walls present a solid square surface to the outside of the corner in conjunction with the solid side walls of the standard blocks. Starter blocks having a planar lower surface with no tongue members are provided to form the first or base course of blocks.
In assembling the block wall structure, the worker applies mortar to either the upper edges of an inferior block or row of blocks or the lower edges of the block to be joined, as well as to the end wall of the adjacent block or the block to be joined. The worker sets the tongue members into the groove members, such that the block is correctly aligned relative to the inferior blocks and adjacent block. Any excess mortar placed into the joint recess is extruded outward by the weight of the block due to the combination of the first and second sloping side walls of the tongue and groove members, where it is easily removed, and any mortar mistakenly deposited in the groove members are on the tongue members will be expressed outwardly due to the chute effect created by the sloping side walls, thus preventing the excess mortar from interfering with proper alignment.